Improvement in crank-expanders



L( SWENSON.

mImprovement in Crank-Expanders.

Patented July 30,1872.

UEITEE STATES PATENT DEEIcE.

LORENS SWENSON,KOF lNORTH CAPE, ASSIGNOR TO HIMSELF AND JOHN B. SMITH, OF MILWAUKEE, WISCONSIN.

iMPROVEM ENT IN 'CRAN K-EXPANDERS.

Specication forming part of Letters Patent No. 129,996, dated July 30, 1872.

SPECIFICATION. A i I, LonENs SWENsoN, of North Cape, in the county of Racine and in theState ot' Wisconsin, have invented certain Improvements in `Orank-Expanders, of which the following is a specication N miur@ cmd vObject of the Invention.

My invention consists in a cam placed on a crank inclosed `Within a frame, so that as the crank in its revolution, when it approaches its position at or nearly at right angles with 'the pitman, Willbe thrown out, thereby lengthening the stroke or leverage of the crank, and when it approaches the dead-points of the stroke the cam Will shorten thehold of the pitman so as to have the crank pass by those points Without increasing the length of the cylinder.

'Description Vof the Drawing forming part of the Specijcaton. Figure 1 is a perspective view of my invenvention, and Fig. 2 a sectional view.

General Description.

balance-wheel; O, bearings or boxes, in whichV the shaft'M runs.

Ihe cam Gr is made one size larger than the other, so that thelarger side may slip in on one side of the roller H, and the small side presses against the roller, while this Wide side strikes against the pin I. This is to regulate the working on the two sides of the stroke piston. The operation of this invention is: as the crank passes around the cam in its movement it increases the length of the pitrnan, and on the outstroke, When a half stroke of the piston is performed, a quarter-revolution of the crank is made, and thus a regular motion is performed, andthe push of the piston is, out from the center of the crank-shaft, faster than an average of the stroke, and the outer portion of the stroke is performed in the same manner, and thus the stroke is equalized, the cam bringing the piston in as it passes the center,

and carryingit out as it approaches the greatest amount of leverage.

Claim.

I claim as my invention- 1. The cam Gr, constructed as described, for the purpose set forth.

2. The cam G, in combination with the crank L, bearings H and I, pitman D, and frame F, substantially as described, and for the purpose 

